The Biology of Senescence 



individuals, were kept for 200-300 days in an attempt to pro- 

 duce gigantism. The end results of this experiment have not yet 

 been reported in full. It would be interesting to know how long 

 such animals are capable of living, and what senile changes 

 they ultimately exhibit. 



Selective suppression of gonadotrophin production is not yet 

 feasible, though recent studies with Lithospermum extracts sug- 

 gest that the chemical 'dissection' of pituitary effects with 

 chemical antagonists is not, perhaps, an unreasonable hope 

 (Wiesner and Yudkin, 1952). The effect upon life-span of 

 inducing precocious puberty in mammals does not appear to 

 have been studied: mice, which mature very early, are not 

 ideal subjects, and an experiment on longer-lived mammals 

 encounters the familiar practical difficulties. 



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